1. Field of the Invention
The invention relates to a method for forming headliners having shaped structural foam beams.
2. Background Art
The covering of the interior surface of a vehicle roof panel is known as a headliner, and may be made and installed in numerous ways. One prior method of making a headliner assembly placed energy absorbing foam pads in the headliner. The pad forming process included molding a block of foam, slicing the block into panels, die-cutting the panels, and compression molding the panels to form the pads. The pads are then attached to a preformed headliner body using assembly dies and an adhesive. Because of the multiple steps involved with forming the pads and attaching the pads to the headliner, this method is time consuming, labor intensive and costly, and also results in significant material waste.
U.S. Pat. No. 5,845,458 discloses another method of making a headliner having deformable foam inserts disposed on side edges of the headliner. The method includes positioning a cover layer, a foam panel, and preformed foam inserts in a mold, and draping a flexible backing layer over the foam panel and foam inserts. Suitable adhesives are also positioned between the cover layer and the foam panel, and between the foam panel and the foam inserts. The mold is then closed to compression mold the foam panel and foam inserts, as well as to stiffen the backing layer. However, this method also involves multiple steps for forming the inserts and attaching the inserts to the remainder of the headliner, complicating and increasing the expense of headliner production.
Another known process applies foam in place technology to provide energy absorbing pads at likely contact areas adjacent to impactable structures, such as roof panel edges. The known method for forming a headliner assembly includes simultaneously forming an energy absorbing member at the likely contact areas and joining the energy absorbing member to a main body of the headliner assembly proximate to the periphery of the body. While the method significantly reduces time and manufacturing costs compared with prior methods for locating and attaching energy absorbing foam pads proximate the periphery of headliners, the method complicates the headliner structure and the handling during production and installation because of the localized pads.
Another known development forms structural beams of foam extending across a major dimension of the headliner. Although such beams can reinforce the headliner to reduce flexing during handling and reduce the difficulty of installing the headliner, the beams are not configured or located for support of accessories or components on the headliners, and are not aligned to address localized acoustic problems.